Cylinder head construction



Dec. 27, 1949 P. KLoTscH ETAL. 2,492,582

CYLINDER HEAD CONSTRUCTION Filed May 4, 1946 .7 jg?. 5 NVENTOR.;

M7@ BY I Patented Dec. 27, 1949 UNITED STATES PATENT OFFICE Ohio, assgnors to Crosley Motors, Inc., Cincinnati, Ohio, a corporation of Ohio Application May 4, 1946, Serial No.

3 Claims. (Cl. 123-193) This invention relates to the fabrication of hydrogen brazed sheet metal engines and lhas pal'-v ticular reference to a stampedl sheet metal cylinder head, press-tted and brazed' upon a seamless steell cylinder sleeve, and the fabrication and assembly of stamped sheet metal valveA bonnets pressedand brazed into openngsor ports of the cylinder head.

The upper portion of the cylinders, cylinder heads and' valve bonnets, in `assembled relation'- ship in the engine, areenclosed'by a water'jacket and are rexteriorl'y `exposed to the c' `olant therein. It is of advantage to form the parts from' light gauge metals to provide for rapid' dissipation of the heat of combustion thereby'improving engine emciencyand providing a light weight assembly. Furthermore, it has' been observed that the utilization of relatively thin walled cylinders and cylinder heads has a decidedly beneficial' effect on engine performance tending toward smoother operationand the eliminationv of knocks under adverse operating conditions.

The cylinder sleeves are therefore formed' of seamless steel tubing having a thickness of approximately 11g but not over gaf of an inch thick. The cylinder heads constitute sheet metal stampings having a thickness of approximately 11s of an' inch, the heads being secured to the cylinders by a press or shrink fit and the joints subsequently brazed. The valve bonnets may be ofv relatively light gaugel sheet metal, for example, of an inch thick, and have their ends pressed and brazed into ports formed inthe headsfor this purpose. The bonnets are not exposed to the direct combustion pressures of the cylinder, serving instead as conduits for the' intake and exhaust passage of the'- gases as' controlled bythe valves of the engine. sheet metal` may be usedin their construction. The valve bonnets are preferably two in number constituting intake and exhaust passageways.

The intake bonnet isv designed' to serve two cylinders and therefore is' in' the form of a U-shaped return bend spanning and connecting the cylinders in pairs.` This bonnet includes a pair of vertical valve stem guide sleeves formed integrally therewith and' in' axial alignment with the cylinder head ports. Each sleeve is adapted to receive a valve stem guide bushing for the valve stem and is seated upon a valve' seat insert which is pressed intov position inits port. The intake bonnetfurther includes a lateral opening communicating With ltleintakt-J -nlani'fold'o'f the' engine-exterior of thewater jacket:

The exhaust portv of? the'v cylinder head is pi-c-A Therefore light gaugey vided with an individual exhaust valve bonnet constituting a right angle elbow having one end securedA in the cylinder head port and its opposite end communicating with an. exhaust manifold to the outside of the Water jacket. This bonnet likewiseincludes a vertical Valve guide sleeve in axial alignment with the exhaust port of the cylinder head as described with reference to the intake valve bonnet.

The complexv coniiguration of the respective valve bonnets presents. an exceedingly diicult stamping operation. Moreover, the stamping necessarily is requiredv to be. within reasonably accurate -limits as' to ccn'centricity and diameter so as'to make the desired light press t with the valve ports and the valve stem sleeves are required to be located within accurate limits with respect to the center of the valve ports so as to properly align the valves with the Valve seat inserts disposedv in the ports. The center-tocenter dimension betweenv the ends of the U-shapedintake bonnet likewise must be within fixedV limits to coliformI to the spacing of the upper ends oi" adjacent cylinders which are connected in paired relationship by the bonnet.

The present invention is predicated upon the concept of fabricating thebonnets of split formation in the form' of two complementary longitudi'nal half sections, each section having a marginal flange, one ofv which is subsequently lapped" over the other'to form a lapped seam, the seam subsequently sealed and rigidied by the penetration of the -brazing material when the assembly is permanently hydrogen brazed in a bracing furnace. This construction permits the use of a preferred grade of steel since the forming operation isa relatively simple one capable oi being performed by stamping as distinguished from drawing which would require a mild steel. The' sectional stamping of the parts provides that the dimensional limits, concentricity and alignment of theassem'bl'e'rl: bonnets may be held within the requiredt'olerances.

It has therefore been an object of the present inventor to provide a sheet metalA valve bonnet and cylinder headE assembly of accurate configuration, concentricity and alignment by forming the bonnet oi" complementary half sections semi-circularv in cross vsection and seamed and permanently brazed' together in matching relationship.

it'has been another object to provide a combine'd cylinder'headf a 'd valve b'onnet construction of' relatively' inexpensive' manufacture', the parts: permanently' united' by bracing to form a unified structure, and formed of sheet metals adapted to lo1/ide a slight degree of resiliency and conducive to rapid heat dissipation iinproved engine performance.

It has 7seen a further object to provide stamped sheet metal valve bonnets oi sectional constr 3- tion joined by a continuous lapped seam united with the cylinder head by a continuous braze which extends without interruption around the seams to permanently join and seal the bonnet sections together and to the cylinder heads as integral unit.

Further objects and advantages of the invention will be more fully apparent from the description of the accompanying drawings, in which:

Figure 1 is an exploded view partially in section, showing the cylinder sleeve, head, and valve bonnets before assembly.

Figure 2 is a sectional view showing the various parts assembled and brazed together as a unit of the internal combustion engine.

Figure 3 is a side view of the exhaust t-'alve bonnet.

Figure e is a sectional view taken on line -Jl, Figure l, detailing the lapped seam joining the respective sections of the intake valve bonnet.

Figure 5 is a cross sectional View of cylinder head, indicated on line -5, Figure l.

Figure 6 is an enlarged sectional view showing the seam before crimping.

Figure 7 is an enlarged sectional view showing the seam after crimping and bracing.

Referring to the drawings, the cylinder sleeve is indicated at E and includes a reduced portion t at its lower end which is adapted to be pressed into an aperture in the base plate l', the base plate providing a flange or mounting plate for the cylinder block. The cylinder head, generally indicated at 8, includes a top wall Q and a iiange portion lll embracing the top of the cylinder sleeve. The liange It of the head includes an enlarged bore portion l i into which is pressed the upper end of the cylinder 5. The top wall 9 of the cylinder head includes a flat area il? as viewed in Figure 1. This provides a flat seat adapted to be engaged by annular beads hereinafter described formed at the lower ends of the valve bonnets and serving to limit the insertion of the bonnets, maintain a proper alignment of the bonnets with the heads and provide a contact surface for a braze iillet between the head and bonnets. As shown in Figure 5 the top of the head at right angles to the bonnets is curved or domed at as i3 and includes a spark plug ren ceivingr boss Hi therein.

The shoulder 5a at the lower end of the cylinder sleeve and the shoulder lia of the cylinder head are accurately located and serve as stops or abut-- ments to limit or control the distance between the bottom of the base plate and the top of the cylinder head when these parts are pressed together in assembly. This distance is critical since it controls the compression ratio of the cylinder engine. In order to maintain this ratio as uniform as possible for all of the cylinders of the engine, the shoulders of all of the cylinders and heads making up the engine assembly are machined uniformly. The area between the top of the cylinder head and the upper limit of piston travel, indicated at ida, constitutes the combustion chamber of the cylinder and as such is exposed to pressures and temperatures of maximum intensity at the moment oi ring. The thin wall section of the cylinder head top is-designed to for the section i8.

induce rapid cooling, therefore resulting in increased engine efiiciency and power output. Its slight inherent resiliency promotes smooth operation and tends to eliminate knocking.

The connection of the cylinder head with the upper end or the cylinder, is accomplished either by a press or shrink t. If a press rit is utilized, a rnetal-to-metal interference is maintained between the diameter or" the aperture oi the base plate and the cylinder head. The parts are then assembled under high pressure, preferably by the use of a hydraulic press. If assembled by a shrink fitting, a temperature differential is accomplished either by raising the temperature of the cylinder head, or by lowering the temperature of the cylinder sleeve. In either event, an appropriate interference provides a pressure t when the parts return to a normal temperature. When the assembly is brazed, brazing material iiows into these pressure constituted joints to provide an integral sealed union between the parts.

The lower end of the cylinder sleeve may be joined to the base plate as above described or alternatively, it may be staked in place in the aperture. In the latter instance a snug t is provided and the lower end of the sleeve extends slightly beyond the lower surface of the base plate. This portion is then flattened or upset at several points around its circumference, for example in a hydraulic press, in eiect riveting the sleeve to the plate. After brazing the excess material is removed in machining the base plate.

As shown, the exhaust valve bonnet i5 is fabricated of two elbow shaped complementary half sections il and it joined longitudinally by the lapped seam generally indicated at i9. The respective sections are generally semi-circular in cross section so as to form a true circle when placed together. As shown, the seam is formed by integral marginal flanges extending around the longitudinal configuration of the respective half sections. The flange 2S for the section il is approximately twice as wide as the iiange 2l These respective half sections are then placed together bringing the anges 2t and 2l together in abutment in a single plane. The wider iiange 2i is then deformed, so as to overlie and clinch the flange 25, by means of suitable clinching dies.

It will be noted that the lower end of the bonnet which is adapted to be pressed into the cylinder head port is provided with a peripheral bead 23, thereby deiining a rim 2d for insertion into the aperture or port 25 of the cylinder head. This rim is formed accurately as to diameter and concentricity so as to make a light press t with the aperture when the bonnet is inserted therein. The bead 23 provides a shoulder to limit the extent to which the rim may be inserted into the cylinder head port, the bead contacting the exterior nat top surface i2 of the head to position and align the bonnet relative to the head as previously described. The rim is of suicient length to extend approximately tof the interior surface of the head to provide a brazing surface for the full wall thickness of the head.

A valve stem guide sleeve 2l is formed as an integral part of the bonnet and extends vertically in axial alignment with the rim 2d and port 25, the seam i9 extending along the opposite sides to the upper end of the sleeve. This sleeve Vis. circular in cross section and is arranged to re-.f ceive a valve stem guide bushing (not shown) --seatsiusertsitugtahmn @are Brasserie which is pressed therein :and begged iin mestieri .to sewerage raide ticrthewalve stem. Naive theralre ports 25 and extended within the ip wer endof the bqnpetgciinchedfin place and subsequently braced. ',Iihis ,complete assembly is disclosed in the copending application of Herbert F. Junkin for Metallic structures :.andwmethod of fabricatsame. Naerial `No. mme. .new Paten- `N0- 2,`486,'654, vto which attention .is invited.

The bonnet is designed to extend from the top of the cylinder lhead Aflaterally ito -the side wall of the awater jacket to connect with an exhaust manifold, secured to the outside of thegjacket. Eer this purpose the discharge end t5 f Qf the .hetnet m1i1deSanannular iatiirned danse .gr lip #6., :Figure 3 This fisl hanged t0 die against vthe inside .surface taf e water jacket to he seagredbvashertgellar mi shown) telescnnically sausages wtherein aud having an .zout- 'ng :the ange 32.6.

varilla' tethered Adans@ essere Theioiitersaldnf .the .QQlIarisfsuitably @arrested to a stiffener plate disposed to the exterior of the jacket to which the manifolds are bolted, the openings of the manifold being in registry with the discharge openings l5 of the bonnets. The design and arrangement above described which is not illustrated, is not an essential part of the present invention; therefore, reference is made to the copending application of Paul Klotsch for Internal combustion engine, Serial No. 662,323, for a more complete disclosure.

The intake valve bonnet 28 constitutes a U- shaped return bend conduit having its respective opposite ends connected to ports 26 of adjacent 'f cylinders. Thus the cylinders are connected in pairs and each valve bonnet serves as a duct for two adjacent cylinders. The bonnet additionally constitutes a reinforcement to strengthen the cylinder and head assembly. By virtue of its arch-like contour, the upward forces imposed upon one head of a pair, at the moment of ring, is resisted by the other, it being understood that the cylinders fire alternately. The joined pair of cylinders thus constitutes a reinforced unit substantially strengthened by the bonnets.

The fabrication of the intake bonnet 28 in general follows the fabrication of the exhaust bonnet I6, being formed stamped half sections joined by a crimped seam I9. In the case of the intake bonnet '28, a pair of vertical valve guide sleeves 21 is provided, each being in axial alignment with the respective rims 24-24 at opposite ends of the bonnet. The beads 23 are located in the same manner as those of the exhaust bonnet and the lapped seam I9 follows the same construction.

Generally described, the intake duct or bonnet is fabricated from a pair of arcuately shaped complementary half sections 33 and 3| semi-circular in cross section and having integral marginal flanges 20 and 2l, as previously described, the wider of the two being clinched to form a return bend overlying the narrower flange, thus forming a single lapped seam. The conguration of the respective half sections is identical with the exception of a lateral passageway 33 formed in the section 3|. This passageway is adapted to receive a sleeve which is brazed thereto to form an extension communicating with an intake manifold in the same manner as previously described with reference to the exhaustbonnet.

By reason of the relatively simple kstamping operation the bonnets may be held within relatively close manufacturing tolerances, thereby providfrom complementary` 'Ill ingian inexpensive lrae,cima-italy -fconstruoted as; sembly. When theitwpfseetionsfare clinchedf-to.- gather `:the .lacencentricity .of :the rim :portions and valyeleeves 'and alignment thereof is .within limits suiieielitly :close iffor proper alignment :of thezyalvesandseats. "iI-hestwofpiece.construction of the ebnnnets .provides f. that 2a ,relatively :hard grade of gsteehmayf-pet'utilized. Thelappedfseam additionally serves ito esti-Tien tand ireinforoe the bonnetsvlongitudinally.

lfIn assembling: the half :sections -to 'zformsa bonnetitheyfareipreferablyfplaced:inasuitablefclinching dies i improper falignment, and the seam |29 ,Sis then stormed, .-.clinching the parts ,rigidly sin fas,- sembly. flheassembledfbonnets arefthenpressed into the ports 26 of the cylinder rhead. .Atfinal assembly of itheiblock .a-brazing iwi-re .isi applied abeutathecircurnference,of .thebonnets adjacent the trim @24, `and a suitable brazingrpaste :.isiapplied to ithe sea-ms i9. `Bra-zingiwi-res .also are applied ato the Lcylinder .-at the juncture of fthe cylinder head andeatfthe ajunoturefofthe. cylinder with the base plate 1 at the bottom. The assembly is then placed in the brazing furnace and a temperature of approximately 2000 Fahrenheit is maintained in a non-oxidizing atmosphere causing the brazing materials to fuse and penetrate into thevarious joints and crevices. The brazed bond provides a permanent union and gas pressure tight seal between the several parts and forms a fillet indicated at 35 (see Figure '7) at the seam in the interior of the bonnets to produce a smooth uninterrupted interior surface.

It has been determined that the joints thus formed have approximately the same strength characteristics as that of the materials from which the parts are fabricated. In this respect, the assembly is similar to a one-piece cast or forged construction but has the added advantages of being a thin wall construction and therefore being resilient, heat transmitting, accurate, and of low cost construction.

After nal assembly and brazing of the cylinder block, the valve stem guide bushings and valve seat inserts are machined for proper running clearances and seating of the valves and the cylinders are machined and accurately bored.

If desired, the valve bonnets and cylinder heads may be assembled and brazed as subassemblies prior to final assembly and brazing of the cylinder block. In this event the valve seat inserts and valve stem guide bushings may be installed in the subassembly and machined prior to nal assembly and brazing, or may be installed and brazed with the 'lnal assembly, then machined.

Having described our invention, we claim:

1. In an vinternal combustion engine the combination of a pair of seamless steel cylinder sleeves, each having a sheet metal cylinder head iltted and brazed thereon, a light gauge sheet metal valve bonnet in the form of an arcuate shaped return bend providing a span between said cylinder heads and having respective opposite open ends, said valve bonnet formed of complementary half sections joined by a lapped and brazed seam following the longitudinal contour of the bonnet centrally thereof, said seam providing a reinforcing rib lto stiien said bonnet, each cylinder head having ports of a size to permit the ends of the bonnet to be pressed therein and permanently united by brazing, to connect the tops of the cylinder sleeves together, and a base plate, the plate having apertures therein to receive the lower ends of the cylinder sleeves, the

sleeves being permanently brazed to said plate to secure their lower ends together.

2. InA an internal combustion engine, the combination of a pair of steel cylinder sleeves, each having a sheet metal cylinder head brazed thereon, a sheet metal valve bonnet Xed to and connecting said cylinder heads, said bonnet comprlsing; two complementary arch-type sheet metal stampngs, said stampings being `ioined in a longitudinal brazed, lapped seam, said seam defining an arch-type, reinforcing rib for said bonnet, said bonnet constituting a reinforced arch between said cylinder heads, whereby each of said cylinders and said arch-type bonnet supports the other of said cylinders during alternate ring of said cylinders.

3; In an internal combustion engine, the cornbination of a pair of steel cylinder sleeves each having a sheet metal cylinder head brazed thereon, an arch-like sheet metal valve bonnet fixed to and connecting said cylinder heads, said bonnet constituting a reinforcing arch span between said cylinder heads, whereby each of said cylin-v ders through said arch-type bonnet supports'the other cylinder head during alternatev ring of said cylinders.

PAUL KLOTSCH. EARL A. TAYLOR.

REFERENCES CITED The'following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 176,835 Carson May 2, 1876 1,113,124 Jacobs Oct. 6, 1914 2,023,354 Cope 1 Dec. 3, 1935 2,071,583 Schutt s Feb. 23, 1937 2,190,719 Y Leighton Feb. 20, 1940 2,199,423 Taylor May 7, 1940 2,275,478 Taylor Mar. 10, 1942 2,337,577 Taylor Dec. 28, 194:3A 2,341,488 Taylor Feb. 8, 1944 

